G'day folks,
My theory is that it slots into the u channel which acts as a guide and maybe this helps support the deck kinda laterally/ torsionally. A small bracket then attaches at the hole In the bar (below your fingers in the photo) to provide a point for the spring to attach to. The other end of the spring is then attached to the frame near the tow point . Set up like that it would act to tension the deck and oppose the belt tension loads.
It's only a theory.........
Cheers
